Compliant perimeter end effectors

ABSTRACT

Various examples are provided related to end effectors for use in, e.g., automation of sewing robots. In one example, among others, a compliant perimeter end effector includes a mounting bracket having a contact mounting flange, a plurality of compliant material contact elements coupled about a perimeter of the contact mounting flange. The mounting bracket can couple to a manipulator including, e.g., an industrial robot or other manipulation assembly. The compliant material contact elements can include a contact interface that can engage with a piece of material. The compliant material contact elements can precisely transfer material on a workspace with surface irregularities while equally distributing force to the material.

BACKGROUND

In automated production of sewn materials, improper handling of thematerial by robotic end effectors to manipulate materials on aworksurface can result in production of out-of-spec products, which hasan immediate economic impact. For example, slip between the materialbeing sewn and the end effector controlling the movement of the materialcan produce flawed and unacceptable product. Material slip can beespecially prevalent for products with non-slip or high frictionbackings (as is common in mats and rugs) as the end effector must applysubstantially more force to the product to move it across a worksurface.

The subject matter discussed in the background section should not beassumed to be prior art merely as a result of its mention in thebackground section. Similarly, a problem mentioned in the backgroundsection or associated with the subject matter of the background sectionshould not be assumed to have been previously recognized in the priorart. The subject matter in the background section merely representsdifferent approaches, which in and of themselves may also correspond toimplementations of the claimed technology.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate various examples of systems,methods, and embodiments of various other aspects of the disclosure. Anyperson with ordinary skills in the art will appreciate that theillustrated element boundaries (e.g., boxes, groups of boxes, or othershapes) in the figures represent one example of the boundaries. It maybe that in some examples one element may be designed as multipleelements or that multiple elements may be designed as one element. Insome examples, an element shown as an internal component of one elementmay be implemented as an external component in another, and vice versa.Furthermore, elements may not be drawn to scale. Non-limiting andnon-exhaustive descriptions are described with reference to thefollowing drawings. The components in the figures are not necessarily toscale, emphasis instead being placed upon illustrating principles.Moreover, in the drawings, like reference numerals designatecorresponding parts throughout the several views.

FIG. 1 illustrates an example of a robotic system, according to variousembodiments of the present disclosure.

FIG. 2A illustrates an example of a compliant perimeter end effector,according to various embodiments of the present disclosure.

FIGS. 2B-2F illustrate examples of compliant material contact elementsof the compliant perimeter end effector of FIG. 2A, according to variousembodiments of the present disclosure.

FIGS. 3A and 3B illustrate another example of a compliant perimeter endeffector, according to various embodiments of the present disclosure.

FIGS. 3C-3G illustrate examples of compliant material contact elementsof the compliant perimeter end effector of FIGS. 3A and 3B, according tovarious embodiments of the present disclosure.

DETAILED DESCRIPTION

Disclosed herein are various examples related to end effectors for usein, e.g., automation of the production of sewn products. For example,compliant material contact elements can be arranged around a perimeterof the end effector to grip and hold the material during processing.Reference will now be made in detail to the description of theembodiments as illustrated in the drawings, wherein like referencenumbers indicate like parts throughout the several views.

The words “comprising,” “having,” “containing,” and “including,” andother forms thereof, are intended to be equivalent in meaning and beopen ended in that an item or items following any one of these words isnot meant to be an exhaustive listing of such item or items, or meant tobe limited to only the listed item or items.

It must also be noted that as used herein and in the appended claims,the singular forms “a,” “an,” and “the” include plural references unlessthe context clearly dictates otherwise. Although any systems and methodssimilar or equivalent to those described herein can be used in thepractice or testing of embodiments of the present disclosure, thepreferred systems and methods are now described.

Embodiments of the present disclosure will be described more fullyhereinafter with reference to the accompanying drawings in which likenumerals represent like elements throughout the several figures, and inwhich example embodiments are shown. Embodiments of the claims may,however, be embodied in many different forms and should not be construedas limited to the embodiments set forth herein. The examples set forthherein are non-limiting examples and are merely examples among otherpossible examples.

Referring to FIG. 1, shown is an example of a system that can be usedfor material manipulation and sewing. As illustrated in the example ofFIG. 1, the system can comprise a robotic system 102, which can includea processor 104, memory 106, an interface such as, e.g., a human machineinterface (HMI) 108, I/O device(s) 110, networking device(s) 112, asewing device 114, material mover(s) 116, secondary operation device(s)118, vision device(s) 120, and a local interface 122. The visiondevice(s) 120 can comprise one or more sensor and/or camera 124 such as,e.g., an RGB camera, an RGB-D camera, a near infrared (NIR) camera,stereoscopic camera, photometric stereo camera (single camera withmultiple illumination options), time of flight camera, IP camera,light-field camera, monorail camera, multiplane camera, rapatroniccamera, still camera, thermal imaging camera, acoustic camera,rangefinder camera, etc. The robotic system 102 can also includeoperational control(s) 126, which can be executed by the robotic system102 to implement manipulation and/or processing of materials. Thematerial mover(s) 116 can comprise end effector(s) 130 which can bemanipulated through one or more manipulator(s) 132 such as, e.g.,industrial robot(s) or other manipulator or appropriate manipulationassembly. Industrial robots include, e.g., articulated robots, selectivecompliance assembly robots (SCARA), delta robots, and cartesiancoordinate robots (e.g., gantry robots or x-y-z robots). Industrialrobots can be programmed to carry out repetitive actions with a highdegree of accuracy or can exhibit more flexibility by utilizing, e.g.,machine vision and machine learning.

The robotic system 102 can grip a piece of product material and move itabout a work area utilizing the material mover(s) 116. For example, anend effector 130 can be moved by a manipulator 132 to engage with apiece of material and manipulate its position and/or orientation forprocessing by the robotic system 102. When the desired processing of thematerial is complete, movement of the end effector 130 can transport thematerial out of the work area. The end effector 130 can then berepositioned by the manipulator 132 to engage with another piece ofmaterial. The piece of material can then be manipulated for processingby the robotic system 102. This automated motion can be very beneficialin many repetitive processes.

The processor 104 can be configured to decode and execute anyinstructions received from one or more other electronic devices orservers. The processor can include one or more general-purposeprocessors (e.g., INTEL® or Advanced Micro Devices® (AMD)microprocessors) and/or one or more special purpose processors (e.g.,digital signal processors or Xilinx® System on Chip (SOC) fieldprogrammable gate array (FPGA) processor). The processor 104 may beconfigured to execute one or more computer-readable programinstructions, such as program instructions to carry out any of thefunctions described in this description.

The Memory 106 can include, but is not limited to, fixed (hard) drives,magnetic tape, floppy diskettes, optical disks, Compact Disc Read-OnlyMemories (CD-ROMs), and magneto-optical disks, semiconductor memories,such as ROMs, Random Access Memories (RAMs), Programmable Read-OnlyMemories (PROMs), Erasable PROMs (EPROMs), Electrically Erasable PROMs(EEPROMs), flash memory, magnetic or optical cards, or other type ofmedia/machine-readable medium suitable for storing electronicinstructions. The Memory 106 can comprise one or more modules (e.g.,operational control(s) 126) that can be implemented as a programexecutable by processor(s) 104.

The interface(s) or HMI 108 can accept inputs from users, provideoutputs to the users, or may perform both the actions. In one case, auser can interact with the interface(s) using one or moreuser-interactive objects and devices. The user-interactive objects anddevices may comprise user input buttons, switches, knobs, levers, keys,trackballs, touchpads, cameras, microphones, motion sensors, heatsensors, inertial sensors, touch sensors, visual indications (e.g.,indicator lights, meters, or screens), audio indications (e.g., bells,buzzers, etc.) or a combination of the above. Further, the interface(s)can either be implemented as a command line interface (CLI), a graphicaluser interface (GUI), a voice interface, or a web-based user-interface,at element 108. The interface(s) can also include combinations ofphysical and/or electronic interfaces, which can be designed based uponthe environmental setting or application.

The input/output devices or I/O devices 110 of the robotic system 102can comprise components used to facilitate connections of the processor104 to other devices such as, e.g., sewing device 114, material mover(s)116, secondary operation device(s) 118 and/or vision device(s) 120 andcan comprise one or more serial, parallel, small system interface(SCSI), universal serial bus (USB), IEEE 1394 (i.e. Firewire™)connection elements or other appropriate connection elements.

The networking device(s) 112 of the robotic system 102 can comprise thevarious components used to transmit and/or receive data over a network.The networking device(s) 112 can include a device that can communicateboth inputs and outputs, for instance, a modulator/demodulator (i.e.modem), a radio frequency (RF) or infrared (IR) transceiver, atelephonic interface, a bridge, a router, as well as a network card,etc.

The sewing device 114 of the robotic system 102 facilitates sewing theproduct materials together and can be configured to sew a perimeter,along markings on the product material, or other paths based on trackinga generated pattern. In additional embodiments, the sewing device 114can include a knife device in order to cut threads, stitches, materialsfrom the workpiece, etc. The material mover(s) 116 of the robotic system102 can facilitate moving the product material(s) during the cutting andsewing operations, at element 116. The secondary operation device(s) 118can include stacking device(s), folding device(s), label manipulationdevice(s), and/or other device(s) that assist with the preparation,making and/or finishing of the sewn product.

The vision device(s) 120 of the robotic system 102 can facilitatedetecting the movement of the product material(s) and inspecting theproduct material(s) for defects and/or discrepancies before, during ofafter a sewing and cutting operation or other process operation.Further, the vision device(s) 120 can facilitate detecting markings onthe product before cutting or sewing the material. A vision device 120can comprise, but is not limited to, an RBG camera, RGB-D camera, nearIR camera, time of flight camera, Internet protocol (IP) camera,light-field camera, monorail camera, multiplane camera, rapatroniccamera, stereo camera, still camera, thermal imaging camera, acousticcamera, rangefinder camera, etc., at element 120. The RGB-D camera is adigital camera that can provide color (RGB) and depth information forpixels in an image.

The local interface 122 of the robotic system 102 can be, for example,but not limited to, one or more buses or other wired or wirelessconnections, as is known in the art. The local interface 122 can haveadditional elements, which are omitted for simplicity, such ascontrollers, buffers (caches), drivers, repeaters, and receivers, toenable communications. Further, the local interface 122 can includeaddress, control, and/or data connections to enable appropriatecommunications among the components, at element 122.

As shown in FIG. 1, the robotic system 102 includes operationalcontrol(s) 126 which can control the robotic system 102 and materialmover(s) 116, as will be discussed. The operational control(s) 126 caninclude one or more process modules that can be executed in order tocontrol operation of various components of the robotic system 102. Forexample, a manipulator 132 (e.g., industrial robot or other manipulationassembly) can be used to manipulate an end effector 130 for moving apiece of material about a worksurface.

Referring now to FIG. 2A, shown is an example of a compliant perimeterend effector 200 that can be used for manipulation of materials on aworksurface of the robotic system 102. The compliant perimeter endeffector 200 comprises a mounting bracket 203 including a contactmounting flange 206 which can be attached to a connector 209 that allowsthe end effector 200 to be coupled to a manipulator 132 (e.g., anindustrial robot). The connector 209 can be, e.g., a releasableconnector (e.g., a quick release blade connection, threaded connection,lever or dial connection, or other type of quick disconnect) configuredto detachably connect to an end of the manipulator 132. The connector209 can be configured to allow for automated changeout of the endeffector 200 by, e.g., an automated tool changer. For example, aselection of end effectors 200 can be positioned on a rotating carouselwhich can facilitate removal of an end effector 200 attached to themanipulator 132 and attachment of another end effector 200 eitherpneumatically or otherwise.

The connector 209 can be attached to the contact mounting flange 206 byscrews, bolts, rivets, or other appropriate fasteners. For example, thefastener can pass through the flange and engage with the connector 209or pass through the connector and engage with the contact mountingflange 206. In other implementations, the connector 209 can be bonded to(e.g., welded, glued, etc.) or integrally formed with the contactmounting flange 206. In some embodiments, the mounting flange can beattached directly to the manipulator 132 by screws, bolts, or otherappropriate fasteners or through a threaded connection in the contactmounting flange 209 without including a connector 209.

As shown in FIG. 2A, the contact mounting flange 206 can comprise asubstantially planar plate (or other structure) for mounting compliantmaterial contact elements 212 to the contact mounting flange 206. In theexample of FIG. 2A, the contact mounting flange 206 is illustrated as asolid plate such as, e.g., a sheet of steel, aluminum, or otherappropriate material. In other implementations, the contact mountingflange 206 can include openings extending through the flange to reducethe weight of the end effector and/or allow for added flexibility of thecontact mounting flange 206. The openings can be arranged in size, shapeand orientation to provide a desired flexibility to the compliantperimeter end effector 200. In some embodiments, the contact mountingflange 206 can include ribs or fins that extend across the length orwidth of the mounting flange, or that radially extend from the connector209 to provide added stiffness or strength to the contact mountingflange 206.

A plurality of compliant material contact elements 212 configured toengage with a piece of material can be mounted around a perimeter of thecontact mounting flange 206. The compliant material contact elements 212provide spring like members that allow the applied force (or load) to bemore evenly distributed around the perimeter of the piece of material.The shape of the contact mounting flange 206 and the arrangement of thecontact elements 212 can vary depending upon the application andmaterial being handled by the end effector 200. For example, while theshape of the contact mounting flange 206 illustrated in FIG. 2A isrectangular, other geometric shapes (e.g., circular, square, hexagonal,octagonal, etc.) or other specialized designs can be utilized tofacilitate appropriate positioning of the compliant material contactelements 212. The distribution and placement of the contact elements 212around the contact mounting flange 206 can be varied to ensure theappropriate contact with the piece of material to facilitate movementand processing by the robotic system 102 (FIG. 1). As can be seen inFIG. 2A, the compliant material contact elements 212 can benon-uniformly positioned (or spaced) around the contact mounting flange206 or can be uniformly distributed about the mounting flange (see,e.g., FIG. 3A). The compliant material contact elements 212 can extendfrom the contact mounting flange 206 at the same angle (e.g.,substantially perpendicular to the edge of the mounting flange 206) orcan extend at different angles (β) with respect to the edge of themounting flange (as illustrated in FIG. 2A). The positioning of thecontact elements 212 can be based on the design of the material beingmanipulated by the end effector 200.

FIG. 2B provides perspective, top, side and front views of an embodimentof the compliant material contact elements 212. Individual compliantmaterial contact elements 212 can include one or more flexure arms 215that extend between the contact mounting flange 206 and a gripping unit218 configured to engage with the piece of material through a contactinterface. For example, the gripping unit 218 can comprise a contactplate 219 with a contact interface 221 that engages with the piece ofmaterial. The contact interface 221 can be an edge (or side) of thecontact plate 219. The flexure arms 215 can extend from a spine (orshoulder) 224 opposite the contact interface 221. The contact interface221 can include teeth or serrations that can penetrate through a portionof the material (e.g., the pile of a rug) for better gripping of thematerial. Various tooth profiles such as triangular, rectangular,rounded or circular may be utilized. A simple triangular tooth profilecan work well to balance the number of contact points, bendingstiffness, and clearance depth for materials with thicker piles such asrugs. A consistent spacing between the teeth (e.g., about 10 mm) allowsfor a more consistent force on each tooth of the gripper unit 218. Inother embodiments, the gripping unit 218 can include a contact pad thatengages with the material. Contact can be made along an edge of thecontact pad or on a planar (or substantially planar) surface of thecontact pad.

In other embodiments of compliant material contact elements 212,compliance can be achieved with the assistance of a spring, as opposedto relying on the flexure of the flexure arms 215. In these embodiments,the flexure arms can be hinged, with spring elements applying a force toimpart rotation about that hinge. Alternately, the gripping unit 218could be spring loaded directly (e.g., straight down). In theseembodiments, the gripping unit can comprise one or more spring-loadedpin(s) that contact the piece of material.

In the example of FIG. 2A, the compliant material contact elements 212include two flexure arms 215 that are attached adjacent to opposite endsof the gripping unit 218. The flexure arms 215 can extend substantiallyperpendicular to a side of the gripping unit 218. The arrangement of theflexure arms 215 can be varied to achieve a desired contact force on thematerial. For example, the flexure arms 215 can taper from a first endto a second end as shown in FIG. 2B, which can assist in thedistribution of stress along the flexure arms 215. In someimplementations, a mounting pad 227 can be included at the end of theflexure arm 215 opposite the gripping unit 218. Screws, bolts, rivets orother appropriate fasteners can be used to connect the flexure arms 215to the contact mounting flange 206.

By having a plurality of compliant material contact elements 212distributed around the contact mounting flange 206, the compliantmaterial contact elements 212 can independently move (e.g., deflect,bend, or twist), which can avoid pinching of the material between theworksurface and the end effector due to surface variations. Forinstance, the independent deflection of the compliant material contactelements 212 can compensate for height variations that may be present inthe worksurface or material. In the example of FIG. 2A, two types ofcompliant material contact elements 212 with different configurationsare utilized. The first elements 212 a extend from the edges of thecontact mounting flange 206 and the second elements 212 b extend fromthe corners of the contact mounting flange 206. As seen in FIG. 2A, thefirst elements 212 a have wider gripping units 218 (e.g., about 90 mm)and narrower flexure arms 215. The second elements 212 b have narrowergripping units 218 (e.g., about 60 mm) and wider flexure arms 215, whichcan account for the longer extension of these flexure arms 215. Thisarrangement can help evenly distribute the force (or load) around theperimeter of the piece of material.

Stiffness of the flexure arms 215 can also be varied between theindividual compliant material contact elements 212 around the contactmounting flange 206. For example, the width or thickness of the flexurearms 215 can be varied to adjust the stiffness of the compliant materialcontact elements 212 at different locations. In some embodiments, theflexure arms 215 can include composite materials or combinations ofmaterials that can provide a desired deflection profile. For example,distributions of carbon fibers can be used to provide the desireddeflection characteristics. The flexure arms 215 can also compriselayers of different materials to achieve specific tension and/orcompression characteristics. Shims (or strips) can also be added ontothe flexure arms 215 of a compliant material contact element 212 toincrease the stiffness. Different types of flexure arms 215 can be usedat different locations across the contact element 212 to provide avarying contact force across the contact interface 221.

As illustrated in FIGS. 2C-2F, the arrangement of the compliant materialcontact elements 212 and their connection to the contact mounting flange206 can be varied. While the flexure arms 215 are substantiallyperpendicular to the contact plate 219 of the contact element 212 inFIG. 2B, the flexure arms 215 can be extended at different angles (θ) asillustrated in FIGS. 2C and 2D. In the example of FIG. 2C, the flexurearms 215 extend substantially parallel to the contact plate 219 of thecontact element 212 and at an angle (θ less than 90 degrees) withrespect to the contact mounting flange 206. In this orientation, thecontact interface 221 engages with the piece of material at an angle(e.g., in a range from about 15 degrees to about 75 degrees or about 30degrees to about 60 degrees) instead of substantially perpendicular tothe material on the worksurface as in FIG. 2B. In the example of FIG.2D, the flexure arms 215 extend at an angle with respect to the contactplate 219 of the contact element 212 and at a corresponding angle withrespect to the contact mounting flange 206. In this orientation, thecontact plate 219 is substantially perpendicular when the contactinterface 221 engages with the piece of material on the worksurface.

FIG. 2E illustrates an example of a compliant material contact element212 with a contact pad 220, with one surface acting as the contactinterface 221. The flexure arms 215 can extend from a backing plateaffixed to the contact pad 220 opposite the contact interface 221. As inthe example of FIG. 2D, the flexure arms 215 extend at an angle withrespect to the contact pad of the contact element 212 and at acorresponding angle with respect to the contact mounting flange 206. InFIG. 2E, the contact pad 220 is oriented so that the surface of thecontact interface 221 is substantially parallel to the material on theworksurface. In other embodiments, the contact pad 220 can be orientedto contact the material on the worksurface at an angle.

FIG. 2F illustrates an example of a compliant material contact element212 coupled to an angled surface of the contact mounting flange 206. Inthis example, the flexure arms 215 extend at an angle with respect tothe contact plate 219 of the contact element 212 and are connected tothe angled surface of the contact mounting flange 206. In thisorientation, the contact plate 219 is substantially perpendicular whenthe contact interface 221 engages with the piece of material on theworksurface. This can also be utilized with a contact pad 220 asillustrated in FIG. 2E. As can be understood, other orientations orcombination of orientations can be utilized in the compliant materialcontact elements 212.

Referring now to FIGS. 3A and 3B, shown are perspective, top and sideviews of another example of a compliant perimeter end effector 300 thatcan be used for manipulation of materials on a worksurface of therobotic system 102. The compliant perimeter end effector 300 comprises amounting bracket 303 including a contact mounting flange 306 which canbe attached to a connector (see, e.g., connector 209 of FIG. 2A) thatallows the end effector 300 to be coupled to a manipulator 132 (e.g., anindustrial robot). The connector can be, e.g., a releasable connector(e.g., a quick release blade connection) configured to detachablyconnect to an end of the manipulator 132. The connector can be attachedto the contact mounting flange 306 by screws, bolts, rivets, or otherappropriate fasteners that can extend through mounting holes in thecontact mounting flange 306. In other implementations, the connector canbe integrally formed with the contact mounting flange 306.

As shown in FIGS. 3A and 3B, the contact mounting flange 306 cancomprise a substantially planar plate with edges (or sides) bentsubstantially perpendicular to the substantially planar plate surfacefor mounting compliant material contact elements 312 of the contactmounting flange 306. In the example of FIGS. 3A and 3B, the contactmounting flange 306 is illustrated as a plate such as, e.g., a sheet ofsteel, aluminum, or other appropriate material with the edges (or sides)extending downward away from the upper surface of the plate. In otherimplementations, the edges (or sides) can extend upward away from thelower surface of the plate. The contact mounting flange 306 can includeopenings extending through the flange to reduce the weight of the endeffector and/or allow for added flexibility of the contact mountingflange 306. The openings can be arranged in size, shape and orientationto provide a desired flexibility to the compliant perimeter end effector300. In FIGS. 3A and 3B, the openings are arranged to provide supportarms that extend to the corners and the sides of the design. In someembodiments, the contact mounting flange 306 can include ribs or finsthat extend across the length or width of the mounting flange, or alongthe support arms, to provide added stiffness or strength to the contactmounting flange 306.

A plurality of compliant material contact elements 312 configured toengage with a piece of material can be mounted around a perimeter of thecontact mounting flange 306. The compliant material contact elements 312provide spring like members that allow the applied force (or load) to bemore evenly distributed around the perimeter of the piece of material.FIG. 3C provides perspective, top, side and front views of an embodimentof the compliant material contact elements 312. Individual compliantmaterial contact elements 312 can include one or more flexure arms 315that extend between a mounting plate 313, which can be coupled oraffixed to the contact mounting flange 306, and a gripping unit 318configured to engage with the piece of material through a contactinterface. For example, the gripping unit 318 can comprise a contact pad320 with a contact interface 321 that engages with the piece ofmaterial. The flexure arms 315 can extend from a backing plate 324affixed to the contact pad 320 opposite the contact interface 321. Thecontact pad 320 can comprise a pad material that engages with a surfaceof the piece of material for better gripping. For example, the padmaterial can have a friction with the piece of material that is abouttwice or more than the friction of the piece of material with theworksurface.

The contact interface 321 can be smooth as illustrated in FIG. 3C or canbe textured or made of a higher friction material to facilitate grippingof the material, and a variety of shapes such as triangular,rectangular, rounded or circular may be utilized. As illustrated inFIGS. 3B and 3C, the gripping unit 318 can be secured at an angle sothat an outer edge of the contact pad 320 first contacts the material.As downward pressure is applied, the flexure arms 314 bend upward toapply additional force to the material. The contact pad 320 can be splitinto sections or partially split to enhance compliance or flexibilitywhen engaged with the piece of material. In other embodiments, thegripping unit 318 can include a contact plate 219 with a contactinterface 221 that engages with the piece of material. Contact can bemade along a contact interface of the contact plate 219, which caninclude teeth or serrations for better gripping of the material. Varioustooth profiles such as triangular, rectangular, rounded or circular maybe utilized as discussed with respect to FIG. 2B.

In the example of FIGS. 3A-3C, the compliant material contact elements312 include two flexure arms 315 that are attached adjacent to themounting plate 313 at opposite ends (or sides) of the gripping unit 318.The flexure arms 315 can extend substantially perpendicular to a side ofthe gripping unit 318. The arrangement of the flexure arms 315 can bevaried to achieve a desired contact force on the material. For example,the flexure arms 315 can taper from a first end to a second end as shownin FIGS. 3B and 3C, which can assist in the distribution of stress alongthe flexure arms 315. In some implementations, mounting pads can beincluded at the end of the flexure arms 315 opposite the gripping unit318 instead of the mounting plate 313. Screws, bolts, rivets or otherappropriate fasteners can be used to connect the mounting plate 313 (orthe flexure arms 315) to the edges (or sides) of the contact mountingflange 306.

By having a plurality of compliant material contact elements 312distributed around the contact mounting flange 306, the compliantmaterial contact elements 312 can independently move (e.g., deflect,bend, or twist). This motion or flexibility can allow the contactinterface of the end effector to better conform with any surface heightvariations in the workpiece or the worksurface, reducing the variationof force applied by the end effector to the workpiece at any givenpoint. More consistent force application can prevent the loss of grip bythe end effector in relative low areas of the workpiece or worksurface,and excessive force or damage to the workpiece in relative high areas ofthe workpiece or worksurface. In the example of FIGS. 3A and 3B, onetype of compliant material contact elements 312 is utilized. Thecompliant material contact elements 312 are shown uniformly distributedabout the contact mounting flange 306. In some embodiments, the size ofthe compliant material contact elements 312 can be varied.

Stiffness of the flexure arms 315 can also be varied between theindividual compliant material contact elements 312 around the contactmounting flange 306. For example, the width or thickness of the flexurearms 315 can be varied to adjust the stiffness of the compliant materialcontact elements 312 at different locations. In some embodiments, theflexure arms 315 can include composite materials or combinations ofmaterials that can provide a desired deflection profile. For example,distributions of carbon fibers can be used to provide the desireddeflection characteristics. The flexure arms 315 can also compriselayers of different materials to achieve specific tension and/orcompression characteristics. Shims (or strips) can also be added ontothe flexure arms 315 of a compliant material contact element 312 toincrease the stiffness. Different types of flexure arms 315 can be usedat different locations across the contact element 312 to provide avarying contact force across the contact interface 321.

As illustrated in FIGS. 3D-3G, the arrangement of the compliant materialcontact elements 312 and their connection to the contact mounting flange306 can be varied. While the flexure arms 315 extend at a downward angleto the contact pad 320 of the contact element 312 in FIGS. 3B and 3C,the flexure arms 315 can be extended substantially parallel with thecontact mounting flange 306 as illustrated in FIG. 3D. In the example ofFIG. 3D, the flexure arms 315 extend substantially parallel to thecontact pad 320 of the contact element 312. In this orientation, thecontact interface 321 engages with the piece of material across thesurface of the contact pad 320.

In other embodiments, the gripping unit 318 can include a contact plate219 with a contact interface 221 that engages with the piece of materialas described with respect to FIGS. 2A-2D. In the example of FIG. 3E, theflexure arms 315 extend substantially parallel to the contact plate 219of the contact element 312 and at an angle (less than 90 degrees) withrespect to the contact mounting flange 306. In this orientation, thecontact interface 321 engages with the piece of material at an angle(e.g., in a range from about 15 degrees to about 75 degrees or about 30degrees to about 60 degrees) instead of substantially perpendicular tothe material on the worksurface. In the example of FIG. 3F, the flexurearms 315 extend at an angle with respect to the contact plate 219 of thecontact element 312 and at a corresponding angle with respect to thecontact mounting flange 306. In this orientation, the contact plate 219is substantially perpendicular when the contact interface 321 engageswith the piece of material on the worksurface.

FIG. 3G illustrates an example of a compliant material contact element312 coupled to an angled surface of the contact mounting flange 306. Inthis example, the flexure arms 315 extend at an angle with respect tothe contact pad 320 of the contact element 312 and are connected to theangled surface of the contact mounting flange 306. In this orientation,the contact pad 320 is substantially parallel when the contact interface321 engages with the piece of material on the worksurface. As can beunderstood, other orientations or combination of orientations can beutilized in the compliant material contact elements 312.

It should be emphasized that the above-described embodiments of thepresent disclosure are merely possible examples of implementations setforth for a clear understanding of the principles of the disclosure.Many variations and modifications may be made to the above-describedembodiment(s) without departing substantially from the spirit andprinciples of the disclosure. All such modifications and variations areintended to be included herein within the scope of this disclosure andprotected by the following claims.

The term “substantially” is meant to permit deviations from thedescriptive term that don't negatively impact the intended purpose.Descriptive terms are implicitly understood to be modified by the wordsubstantially, even if the term is not explicitly modified by the wordsubstantially.

It should be noted that ratios, concentrations, amounts, and othernumerical data may be expressed herein in a range format. It is to beunderstood that such a range format is used for convenience and brevity,and thus, should be interpreted in a flexible manner to include not onlythe numerical values explicitly recited as the limits of the range, butalso to include all the individual numerical values or sub-rangesencompassed within that range as if each numerical value and sub-rangeis explicitly recited. To illustrate, a concentration range of “about0.1% to about 5%” should be interpreted to include not only theexplicitly recited concentration of about 0.1 wt % to about 5 wt %, butalso include individual concentrations (e.g., 1%, 2%, 3%, and 4%) andthe sub-ranges (e.g., 0.5%, 1.1%, 2.2%, 3.3%, and 4.4%) within theindicated range. The term “about” can include traditional roundingaccording to significant figures of numerical values. In addition, thephrase “about ‘x’ to ‘y’” includes “about ‘x’ to about ‘y’”.

Therefore, at least the following is claimed:
 1. A compliant perimeterend effector, comprising: a mounting bracket having a contact mountingflange, the mounting bracket configured to couple to a manipulator; anda plurality of compliant material contact elements comprising individualcontact elements coupled about a perimeter of the contact mountingflange, wherein each of the individual contact elements comprises: agripping unit having a contact interface configured to engage with apiece of material; and at least one flexure arm extending between thegripping unit and the perimeter of the contact mounting flange.
 2. Thecompliant perimeter end effector of claim 1, wherein the individualcontact elements comprise at least two flexure arms.
 3. The compliantperimeter end effector of claim 2, wherein a first flexure arm isattached to a first end of the gripping unit and a second flexure arm isattached to a second end of the gripping unit.
 4. The compliantperimeter end effector of claim 3, wherein the individual contactelements of the plurality of compliant material contact elementscomprise a mounting plate extending between the first and second flexurearms opposite the gripping unit, wherein the mounting plate is coupledto the perimeter of the contact mounting flange.
 5. The compliantperimeter end effector of claim 4, wherein the mounting plate comprisesa first portion that is substantially parallel with the first and secondflexure arms, and a second portion extending at an angle with respect tothe first and second flexure arms.
 6. The compliant perimeter endeffector of claim of claim 5, wherein the angle is in a range from about90 degrees to about 110 degrees.
 7. The compliant perimeter end effectorof claim 1, wherein a width of the at least one flexure arm tapers froma proximal end coupled to the contact mounting flange to a distal endattached to the gripping unit.
 8. The compliant perimeter end effectorof claim 1, wherein the gripping unit comprises a contact platecomprising the contact interface, the contact plate attached to the atleast one flexure arm.
 9. The compliant perimeter end effector of claimof claim 8, wherein the at least one flexure arm extends substantiallyperpendicular to the contact plate.
 10. The compliant perimeter endeffector of claim 9, wherein the contact plate extends between first andsecond flexure arms.
 11. The compliant perimeter end effector of claim8, wherein the contact interface comprises teeth or serrations extendingacross the contact plate.
 12. The compliant perimeter end effector ofclaim 11, wherein the tips of the teeth are rounded.
 13. The compliantperimeter end effector of claim 1, wherein the gripping unit comprises acontact pad comprising the contact interface, the contact pad attachedto a backing plate attached to the at least one flexure arm.
 14. Thecompliant perimeter end effector of claim 13, wherein the contact padcomprises a substantially planar contact interface.
 15. The compliantperimeter end effector of claim 13, wherein the contact interfacecomprises an edge of the contact pad.
 16. The compliant perimeter endeffector of claim 1, wherein the contact mounting flange comprises asubstantially planar surface.
 17. The compliant perimeter end effectorof claim 16, wherein the at least one flexure arm is substantiallyparallel with the substantially planar surface.
 18. The compliantperimeter end effector of claim 16, wherein the contact mounting flangecomprises edges bent substantially perpendicular to the substantiallyplanar surface.
 19. The compliant perimeter end effector of claim 18,wherein the at least one flexure arm is coupled to at least one of theedges via a mounting plate.
 20. The compliant perimeter end effector ofclaim 16, wherein the substantially planar surface comprises openingsextending through the contact mounting flange.